xfrm: add an interface to offload policy

Extend netlink interface to add and delete XFRM policy from the device.
This functionality is a first step to implement packet IPsec offload solution.
Signed-off-by: Raed Salem <raeds@nvidia.com>
Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

include/linux/netdevice.h

@@ -1040,6 +1040,9 @@ struct xfrmdev_ops {
 	bool	(*xdo_dev_offload_ok) (struct sk_buff *skb,
 				       struct xfrm_state *x);
 	void	(*xdo_dev_state_advance_esn) (struct xfrm_state *x);
+	int	(*xdo_dev_policy_add) (struct xfrm_policy *x);
+	void	(*xdo_dev_policy_delete) (struct xfrm_policy *x);
+	void	(*xdo_dev_policy_free) (struct xfrm_policy *x);
 };
 #endif
 

include/net/xfrm.h

@@ -129,6 +129,7 @@ struct xfrm_state_walk {
 enum {
 	XFRM_DEV_OFFLOAD_IN = 1,
 	XFRM_DEV_OFFLOAD_OUT,
+	XFRM_DEV_OFFLOAD_FWD,
 };
 
 enum {
@@ -541,6 +542,8 @@ struct xfrm_policy {
 	struct xfrm_tmpl       	xfrm_vec[XFRM_MAX_DEPTH];
 	struct hlist_node	bydst_inexact_list;
 	struct rcu_head		rcu;
+
+	struct xfrm_dev_offload xdo;
 };
 
 static inline struct net *xp_net(const struct xfrm_policy *xp)
@@ -1585,6 +1588,8 @@ struct xfrm_state *xfrm_find_acq_byseq(struct net *net, u32 mark, u32 seq);
 int xfrm_state_delete(struct xfrm_state *x);
 int xfrm_state_flush(struct net *net, u8 proto, bool task_valid, bool sync);
 int xfrm_dev_state_flush(struct net *net, struct net_device *dev, bool task_valid);
+int xfrm_dev_policy_flush(struct net *net, struct net_device *dev,
+			  bool task_valid);
 void xfrm_sad_getinfo(struct net *net, struct xfrmk_sadinfo *si);
 void xfrm_spd_getinfo(struct net *net, struct xfrmk_spdinfo *si);
 u32 xfrm_replay_seqhi(struct xfrm_state *x, __be32 net_seq);
@@ -1899,6 +1904,9 @@ struct sk_buff *validate_xmit_xfrm(struct sk_buff *skb, netdev_features_t featur
 int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 		       struct xfrm_user_offload *xuo,
 		       struct netlink_ext_ack *extack);
+int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
+			struct xfrm_user_offload *xuo, u8 dir,
+			struct netlink_ext_ack *extack);
 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x);
 
 static inline void xfrm_dev_state_advance_esn(struct xfrm_state *x)
@@ -1947,6 +1955,28 @@ static inline void xfrm_dev_state_free(struct xfrm_state *x)
 		netdev_put(dev, &xso->dev_tracker);
 	}
 }
+
+static inline void xfrm_dev_policy_delete(struct xfrm_policy *x)
+{
+	struct xfrm_dev_offload *xdo = &x->xdo;
+	struct net_device *dev = xdo->dev;
+
+	if (dev && dev->xfrmdev_ops && dev->xfrmdev_ops->xdo_dev_policy_delete)
+		dev->xfrmdev_ops->xdo_dev_policy_delete(x);
+}
+
+static inline void xfrm_dev_policy_free(struct xfrm_policy *x)
+{
+	struct xfrm_dev_offload *xdo = &x->xdo;
+	struct net_device *dev = xdo->dev;
+
+	if (dev && dev->xfrmdev_ops) {
+		if (dev->xfrmdev_ops->xdo_dev_policy_free)
+			dev->xfrmdev_ops->xdo_dev_policy_free(x);
+		xdo->dev = NULL;
+		netdev_put(dev, &xdo->dev_tracker);
+	}
+}
 #else
 static inline void xfrm_dev_resume(struct sk_buff *skb)
 {
@@ -1974,6 +2004,21 @@ static inline void xfrm_dev_state_free(struct xfrm_state *x)
 {
 }
 
+static inline int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
+				      struct xfrm_user_offload *xuo, u8 dir,
+				      struct netlink_ext_ack *extack)
+{
+	return 0;
+}
+
+static inline void xfrm_dev_policy_delete(struct xfrm_policy *x)
+{
+}
+
+static inline void xfrm_dev_policy_free(struct xfrm_policy *x)
+{
+}
+
 static inline bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 {
 	return false;

net/xfrm/xfrm_device.c

@@ -325,6 +325,69 @@ int xfrm_dev_state_add(struct net *net, struct xfrm_state *x,
 }
 EXPORT_SYMBOL_GPL(xfrm_dev_state_add);
 
+int xfrm_dev_policy_add(struct net *net, struct xfrm_policy *xp,
+			struct xfrm_user_offload *xuo, u8 dir,
+			struct netlink_ext_ack *extack)
+{
+	struct xfrm_dev_offload *xdo = &xp->xdo;
+	struct net_device *dev;
+	int err;
+
+	if (!xuo->flags || xuo->flags & ~XFRM_OFFLOAD_PACKET) {
+		/* We support only packet offload mode and it means
+		 * that user must set XFRM_OFFLOAD_PACKET bit.
+		 */
+		NL_SET_ERR_MSG(extack, "Unrecognized flags in offload request");
+		return -EINVAL;
+	}
+
+	dev = dev_get_by_index(net, xuo->ifindex);
+	if (!dev)
+		return -EINVAL;
+
+	if (!dev->xfrmdev_ops || !dev->xfrmdev_ops->xdo_dev_policy_add) {
+		xdo->dev = NULL;
+		dev_put(dev);
+		NL_SET_ERR_MSG(extack, "Policy offload is not supported");
+		return -EINVAL;
+	}
+
+	xdo->dev = dev;
+	netdev_tracker_alloc(dev, &xdo->dev_tracker, GFP_ATOMIC);
+	xdo->real_dev = dev;
+	xdo->type = XFRM_DEV_OFFLOAD_PACKET;
+	switch (dir) {
+	case XFRM_POLICY_IN:
+		xdo->dir = XFRM_DEV_OFFLOAD_IN;
+		break;
+	case XFRM_POLICY_OUT:
+		xdo->dir = XFRM_DEV_OFFLOAD_OUT;
+		break;
+	case XFRM_POLICY_FWD:
+		xdo->dir = XFRM_DEV_OFFLOAD_FWD;
+		break;
+	default:
+		xdo->dev = NULL;
+		dev_put(dev);
+		NL_SET_ERR_MSG(extack, "Unrecognized oflload direction");
+		return -EINVAL;
+	}
+
+	err = dev->xfrmdev_ops->xdo_dev_policy_add(xp);
+	if (err) {
+		xdo->dev = NULL;
+		xdo->real_dev = NULL;
+		xdo->type = XFRM_DEV_OFFLOAD_UNSPECIFIED;
+		xdo->dir = 0;
+		netdev_put(dev, &xdo->dev_tracker);
+		NL_SET_ERR_MSG(extack, "Device failed to offload this policy");
+		return err;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(xfrm_dev_policy_add);
+
 bool xfrm_dev_offload_ok(struct sk_buff *skb, struct xfrm_state *x)
 {
 	int mtu;
@@ -427,8 +490,10 @@ static int xfrm_api_check(struct net_device *dev)
 
 static int xfrm_dev_down(struct net_device *dev)
 {
-	if (dev->features & NETIF_F_HW_ESP)
+	if (dev->features & NETIF_F_HW_ESP) {
 		xfrm_dev_state_flush(dev_net(dev), dev, true);
+		xfrm_dev_policy_flush(dev_net(dev), dev, true);
+	}
 
 	return NOTIFY_DONE;
 }

net/xfrm/xfrm_policy.c

@@ -425,6 +425,7 @@ void xfrm_policy_destroy(struct xfrm_policy *policy)
 	if (del_timer(&policy->timer) || del_timer(&policy->polq.hold_timer))
 		BUG();
 
+	xfrm_dev_policy_free(policy);
 	call_rcu(&policy->rcu, xfrm_policy_destroy_rcu);
 }
 EXPORT_SYMBOL(xfrm_policy_destroy);
@@ -1769,12 +1770,41 @@ xfrm_policy_flush_secctx_check(struct net *net, u8 type, bool task_valid)
 	}
 	return err;
 }
+
+static inline int xfrm_dev_policy_flush_secctx_check(struct net *net,
+						     struct net_device *dev,
+						     bool task_valid)
+{
+	struct xfrm_policy *pol;
+	int err = 0;
+
+	list_for_each_entry(pol, &net->xfrm.policy_all, walk.all) {
+		if (pol->walk.dead ||
+		    xfrm_policy_id2dir(pol->index) >= XFRM_POLICY_MAX ||
+		    pol->xdo.dev != dev)
+			continue;
+
+		err = security_xfrm_policy_delete(pol->security);
+		if (err) {
+			xfrm_audit_policy_delete(pol, 0, task_valid);
+			return err;
+		}
+	}
+	return err;
+}
 #else
 static inline int
 xfrm_policy_flush_secctx_check(struct net *net, u8 type, bool task_valid)
 {
 	return 0;
 }
+
+static inline int xfrm_dev_policy_flush_secctx_check(struct net *net,
+						     struct net_device *dev,
+						     bool task_valid)
+{
+	return 0;
+}
 #endif
 
 int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
@@ -1814,6 +1844,44 @@ int xfrm_policy_flush(struct net *net, u8 type, bool task_valid)
 }
 EXPORT_SYMBOL(xfrm_policy_flush);
 
+int xfrm_dev_policy_flush(struct net *net, struct net_device *dev,
+			  bool task_valid)
+{
+	int dir, err = 0, cnt = 0;
+	struct xfrm_policy *pol;
+
+	spin_lock_bh(&net->xfrm.xfrm_policy_lock);
+
+	err = xfrm_dev_policy_flush_secctx_check(net, dev, task_valid);
+	if (err)
+		goto out;
+
+again:
+	list_for_each_entry(pol, &net->xfrm.policy_all, walk.all) {
+		dir = xfrm_policy_id2dir(pol->index);
+		if (pol->walk.dead ||
+		    dir >= XFRM_POLICY_MAX ||
+		    pol->xdo.dev != dev)
+			continue;
+
+		__xfrm_policy_unlink(pol, dir);
+		spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
+		cnt++;
+		xfrm_audit_policy_delete(pol, 1, task_valid);
+		xfrm_policy_kill(pol);
+		spin_lock_bh(&net->xfrm.xfrm_policy_lock);
+		goto again;
+	}
+	if (cnt)
+		__xfrm_policy_inexact_flush(net);
+	else
+		err = -ESRCH;
+out:
+	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
+	return err;
+}
+EXPORT_SYMBOL(xfrm_dev_policy_flush);
+
 int xfrm_policy_walk(struct net *net, struct xfrm_policy_walk *walk,
 		     int (*func)(struct xfrm_policy *, int, int, void*),
 		     void *data)
@@ -2245,6 +2313,7 @@ int xfrm_policy_delete(struct xfrm_policy *pol, int dir)
 	pol = __xfrm_policy_unlink(pol, dir);
 	spin_unlock_bh(&net->xfrm.xfrm_policy_lock);
 	if (pol) {
+		xfrm_dev_policy_delete(pol);
 		xfrm_policy_kill(pol);
 		return 0;
 	}

net/xfrm/xfrm_user.c

@@ -1892,6 +1892,15 @@ static struct xfrm_policy *xfrm_policy_construct(struct net *net,
 	if (attrs[XFRMA_IF_ID])
 		xp->if_id = nla_get_u32(attrs[XFRMA_IF_ID]);
 
+	/* configure the hardware if offload is requested */
+	if (attrs[XFRMA_OFFLOAD_DEV]) {
+		err = xfrm_dev_policy_add(net, xp,
+					  nla_data(attrs[XFRMA_OFFLOAD_DEV]),
+					  p->dir, extack);
+		if (err)
+			goto error;
+	}
+
 	return xp;
  error:
 	*errp = err;
@@ -1931,6 +1940,7 @@ static int xfrm_add_policy(struct sk_buff *skb, struct nlmsghdr *nlh,
 	xfrm_audit_policy_add(xp, err ? 0 : 1, true);
 
 	if (err) {
+		xfrm_dev_policy_delete(xp);
 		security_xfrm_policy_free(xp->security);
 		kfree(xp);
 		return err;
@@ -2043,6 +2053,8 @@ static int dump_one_policy(struct xfrm_policy *xp, int dir, int count, void *ptr
 		err = xfrm_mark_put(skb, &xp->mark);
 	if (!err)
 		err = xfrm_if_id_put(skb, xp->if_id);
+	if (!err && xp->xdo.dev)
+		err = copy_user_offload(&xp->xdo, skb);
 	if (err) {
 		nlmsg_cancel(skb, nlh);
 		return err;
@@ -3381,6 +3393,8 @@ static int build_acquire(struct sk_buff *skb, struct xfrm_state *x,
 		err = xfrm_mark_put(skb, &xp->mark);
 	if (!err)
 		err = xfrm_if_id_put(skb, xp->if_id);
+	if (!err && xp->xdo.dev)
+		err = copy_user_offload(&xp->xdo, skb);
 	if (err) {
 		nlmsg_cancel(skb, nlh);
 		return err;
@@ -3499,6 +3513,8 @@ static int build_polexpire(struct sk_buff *skb, struct xfrm_policy *xp,
 		err = xfrm_mark_put(skb, &xp->mark);
 	if (!err)
 		err = xfrm_if_id_put(skb, xp->if_id);
+	if (!err && xp->xdo.dev)
+		err = copy_user_offload(&xp->xdo, skb);
 	if (err) {
 		nlmsg_cancel(skb, nlh);
 		return err;
@@ -3582,6 +3598,8 @@ static int xfrm_notify_policy(struct xfrm_policy *xp, int dir, const struct km_e
 		err = xfrm_mark_put(skb, &xp->mark);
 	if (!err)
 		err = xfrm_if_id_put(skb, xp->if_id);
+	if (!err && xp->xdo.dev)
+		err = copy_user_offload(&xp->xdo, skb);
 	if (err)
 		goto out_free_skb;